Acoustic emission experiment of rock failure under coupled static-dynamic load

The acoustic emission(AE) tests of rock failure were made on the SHPB test system and the law of the AE energy was obtained under coupled static-dynamic load. The AE energy presents two different features:mode I,the energy decays rapidly after the peak of the energy,however,the energy rises at the end of the loading and the inflection point appears; mode II,the energy decays slowly after the peak of the energy and the inflection point does not appear. The effect of the axial static load and impact on the AE energy was analyzed. The results show that the peak value of the AE energy decreases with the increase of the axial static load; when the axial static load is located at the elastic stage,the pre-peak of the AE energy increases slowly; when the axial static load exceeds the elastic stage,the pre-peak of the AE energy increases rapidly with the increase of the axial static load. The peak and pre-peak of the AE energy decrease with the increase of the dynamic strain rate. It is useful for both theory and practice to seek the precursory characteristics of the AE of rock mass under coupled static-dynamic load.